Thermal effect of the microwave Mach-Zehnder interferometric switch

The triggered-phase transient analyzer (TPTA) was developed in our laboratory recently. With TPTA, the phase transient of Mach-Zehnder interferometric switch which was used to reduce the microwave leakage was studied. From the measurement results, it seemed that there were some kinds of thermal effect in our interferometric switch. The TPTA has the ability to measure the phase variations of two pulsed microwaves with a fixed interval in one cycle. Therefore, after measuring the phase discontinuity between two switching on states in one fountain clock's cycle, the frequency uncertainty induced by interferometric switch was reported in this paper.